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24-26 September 2008, Rome, Italy2002 20 o C40 o C1.660 o C180160140Case, a)No heatingIc [A]1.2PM [W]120100Case, b)800.8600.44020000 0.1 0.2 0.3 0.4 0.5 0.6 0.7V c [V]0 10 20 30 40 50 60 70 80 90 100V M [V]Fig. 5.Single cell I-V characteristic.Fig. 7.Power versus voltage module characteristic.IM [A]2.421.61.20.80.4Case, b)No heatingCase, a)00 10 20 30 40 50 60 70 80 90 100V M [V]Fig. 6.String module characteristic.results in a mild heating of the cells and in a maximumsuppliable power of about 168 W. In the case b) the low fluidspeed results in a significant cells heating and in a reductionof maximum suppliable power of 152 W. This, on the otherhand, corresponds to a higher temperature of the outcomingfluid and thus to a greater energy stored in it. This highlightsthe fact that by controlling the fluid speed it is possible to tradebetween electrical power production and fluid energy storage.material employed and the enhancement of overall energeticefficiency which is introduced by the heat recovery effect.It has been shown how the temperature profile along thecells can be evaluated through a simple equivalent circuitalmodel of the heat exchange mechanism with the fluid.The I-V electrical characteristic of the whole panel has beenderived as a function of the speed of the incoming fluid.REFERENCES[1] A. Luque, Handbook of Photovoltaic Science and Engineering, NewYork: Wiley, 2003.[2] L. Castaner, S. Silvestre, Modeling photovoltaic systems using PSpice,John Wiley & Sons., England, 2002.[3] N. Femia, G. Petrone, G. Spagnuolo, and M. Vitelli, “Optimization ofPerturb and Observe Maximum Power Point Tracking Method,” IEEETrans. Power Electronics, Vol. 20, No. 4. Jul. 2005, pp. 963-973.[4] Walker, G. R. and Sernia, “Cascaded DC-DC converter connection ofphotovoltaic modules,” IEEE Trans. Power Electronics, Vol.19, No.4,2004, pp. 1130-1139.[5] D. Shmilovitz, S. Singer, “Interfacing photovoltaic panels via a capacitiveconverter,” Proc. 22-nd Convention of Electrical and ElectronicsEngineers in Israel, Tel-Aviv, Israel, Dec. 2002, pp. 160-162.[6] G.R. Walker, “Evaluating MPPT converter topologies using a MATLABPV model,” Journal of Electrical & Electronics Engineering, Australia,Vol.21, No.1, pp. 49-56.[7] F. P. Incoprera, D. P. Dewitt, Introduction to heat transfer, John Willey& Sons, 1981.[8] P. Maffezzoni, L. Codecasa, D. D’Amore, “Event-Driven Time DomainSimulation of Closed-Loop Switched Circuits”, IEEE Trans. onComputer-Aided-Design of Integrated Circuits and Systems, Vol.25,N.11, Nov. 2006, pp. 2413-2426.V. CONCLUSIONThis paper has presented a multi-physics analysis of ahybrid photovoltaic system formed by a single string of seriesconnected solar cells, a solar concentrator and a coolingmechanism with heat recovery.The system represents a promising solution for renewableenergy production due to the limited amount of raw silicon©EDA Publishing/THERMINIC 2008 96ISBN: 978-2-35500-008-9